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  • 151.
    Hutchinson, Bevis
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Critical assessment 16: Anisotropy in metals2015Ingår i: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 31, nr 12, s. 1393-1401Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Sources of anisotropy in metals are discusssed as well as ways of interpreting and modelling this behaviour. A number of case studies are presented relating to mechanical and magnetic properties.

  • 152.
    Hutchinson, Bevis
    RISE, Swerea, Swerea KIMAB AB.
    Origin of goss texture during secondary recrystallisation in silicon-steel2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    Primary recrystallised sheets of 3% silicon steel from two different industrial processing routes have been examined after laboratory annealing to initiate secondary recrystallisation. Metallography included etching to reveal individual dislocations and sub-boundaries as well as EBSD in scanning electron microscopy. Residual low angle boundaries are not normally observed inside the secondary grains. The growth of secondaries appears to occur in a jerky manner, associated with local intrusions into the primary matrix that destabilise the interface. The frequency of occurrence of special low energy grain boundaries such as ∑9 and ∑5 is believed to dictate the selectivity of the Goss orientation in both types of steel sheet. © (2012) Trans Tech Publications, Switzerland.

  • 153.
    Hutchinson, Bevis
    et al.
    RISE, Swerea, Swerea KIMAB AB.
    Barnett, M.R.
    Deakin University.
    Ghaderi, A.
    Deakin University.
    Cizek, P.
    Deakin University.
    Sabirov, I.
    Deakin University.
    Deformation modes and anisotropy in magnesium alloy AZ312009Ingår i: International Journal of Materials Research - Zeitschrift für Metallkunde, ISSN 1862-5282, E-ISSN 2195-8556, Vol. 100, nr 4, s. 556-563Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A strongly textured sheet of magnesium alloy AZ31 has been subjected to tensile testing at temperatures between ambient and 300 °C. Structures have been examined by optical and transmission electron microscopy and also by atomic force microscopy to quantify surface displacements seen at grain boundaries. Plastic anisotropy varies strongly with test temperature as was observed previously by Agnew and Duygulu. The present findings do not support the view that crystallographic <c + a> becomes a major contributor to deformation at higher temperatures. Rather, the material behaviour reflects an increasing contribution from grain boundary sliding despite the relatively high strain rate (10-3 s-1 ) used in the mechanical tests. © Carl Hanser Verlag GmbH & Co. KG.

  • 154.
    Hutchinson, Bevis
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB.
    Bate, Pete
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB.
    Lindell, David
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB.
    Malik, Amer
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB.
    Barnett, Matthew
    Deakin University, Australia.
    Lynch, Peter
    Deakin University, Australia.
    Plastic yielding in lath martensites – An alternative viewpoint2018Ingår i: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 152, s. 239-247Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In recent literature the gradual yielding of quenched martensitic steels has been attributed to either heterogeneous microstructures having different strength levels or to the presence of small scale, Type II, residual stresses. Using in-situ tensile testing in synchrotron diffraction experiments in combination with crystal plasticity finite element modelling (CPFEM) we show that the dominant influence on yielding derives from the residual stresses which are a product of the displacive transformation from austenite during quenching. As plastic straining proceeds, the measured diffraction peaks become narrower and asymmetric, as predicted by the CPFEM calculations. The model predictions are generally in good agreement with published results showing large variations in local strains in different microstructural elements.

  • 155.
    Hutchinson, Bevis
    et al.
    RISE, Swerea, Swerea KIMAB AB.
    Hagström, Joacim
    RISE, Swerea, Swerea KIMAB AB.
    Karlsson, Oskar
    RISE, Swerea, Swerea KIMAB AB.
    Lindell, David
    RISE, Swerea, Swerea KIMAB AB.
    Tornberg, Malin
    RISE, Swerea, Swerea KIMAB AB.
    Lindberg, Fredrik
    RISE, Swerea, Swerea KIMAB AB.
    Thuvander, M.
    Chalmers University of Technology.
    Microstructures and hardness of as-quenched martensites (0.1-0.5%C)2011Ingår i: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 59, nr 14, s. 5845-5858Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Four commercial steels with carbon contents in the range 0.1-0.5 wt.% have been examined in the as-quenched condition using electron microscopy, X-ray diffraction and atom probe tomography. The austenite had been deformed 0%, 10% and 30% prior to brine quenching. No influence of this deformation was evident on the martensite hardness or in any of the microstructure measurements. Increasing carbon content showed a well-known marked effect on the hardness but resulted in little refinement in the grain structure of the martensite. All crystal structures were cubic; no evidence of tetragonality was seen even at the highest carbon level but some systematic changes in grain boundary misorientations existed. The content of carbon in true interstitial solid solution deduced from X-ray line shifts was small (∼0.02 wt.%), and was independent of the total carbon content in the steel. Atom probe tomography showed that carbon was almost completely segregated to lath boundaries and dislocations but with an increasing density of segregates in the higher carbon steels. Calculations of diffusion distances confirmed that the segregation patterns were compatible with autotempering of the martensite during quenching. Analysis of different possible contributions to strength leads to the conclusion that segregated carbon atoms at defects behave similarly to carbon in true solid solution and that this is the largest single factor controlling the strength of as-quenched martensite. © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  • 156.
    Hutchinson, Bevis
    et al.
    RISE, Swerea, Swerea KIMAB AB.
    Hallstadius, L.
    Westinghouse Electric Sweden.
    Oxidation of Zircaloy-2 studied using a wedge-shaped specimen2013Ingår i: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 432, s. 437-443Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Experiments have been carried out to vary the stress in the oxide layer during oxidation of Zircaloy-2. This was achieved by varying the thickness of the metal substrate, using a specimen with a tapered wedge-shaped cross-section. X-ray diffraction measurements confirmed that the compressive stress level in the oxide was reduced when the metal substrate was thinner. The rate of oxidation was also slower for conditions where the stress was reduced. The results can be interpreted such that transitions in the growth result from sequential cracking of the oxide when sufficient elastic strain energy accumulates and that the cracks then enhance access of oxygen to the metal interface. © 2012 Elsevier B.V. All rights reserved.

  • 157.
    Hutchinson, Bevis
    et al.
    RISE, Swerea, Swerea KIMAB AB.
    Jain, J.
    Deakin University.
    Barnett, M.R.
    Deakin University.
    A minimum parameter approach to crystal plasticity modelling2012Ingår i: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 60, nr 15, s. 5391-5398Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Plastic deformation processes in hexagonal metals are complex and are best analyzed using procedures such as visco-plastic self-consistent crystal plasticity modelling. These involve a large number of adjustable parameters and make limited use of independent input data. Using physical arguments, the authors show that several of the parameters can be replaced by experimentally measured values of critical resolved shear stresses from the literature. A further simplification derives from the argument that all deformation modes interact with the same substructure, and so a common work-hardening behaviour can be assumed as a reasonable first approximation. Furthermore, many microstructural contributions to the strength can be introduced through a single constant term. In these ways, the twelve or more adjustable parameters in the model are reduced to only three. This new approach is tested critically by applying it to a sheet magnesium alloy for which the plastic strain ratio varies markedly during the test. Its complex plastic behaviour, which arises from changes among the active deformation modes, is successfully predicted. A benefit of the present approach is that the effect of metallurgical variables such as grain size or precipitation strengthening can be readily investigated. Although tested here for a magnesium alloy, the same principles should be applicable to other hexagonal close-packed materials. © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  • 158.
    Hutchinson, Bevis
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Lindell, David
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Barnett, Matthew
    Deakin University, Australia.
    Yielding behaviour of martensite in steel2015Ingår i: ISIJ International, ISSN 0915-1559, E-ISSN 1347-5460, Vol. 55, nr 5, s. 1114-1122Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Although martensite is recognised as a very strong phase in carbon steels, its initial yielding commences at low stresses and the tensile stress-strain curve shows a smooth, rounded form. Evidence is presented from x-ray diffraction to show that this behaviour is due to the presence of intra-granular stresses that are residues after the shear transformation from austenite to martensite. These internal stresses are reduced in magnitude by plastic deformation and also by tempering. Reduction of internal stress due to plasticity is shown by a decrease in XRD line broadening after deformation. A simple model is presented in which the stress-strain behaviour is controlled by relaxation of the internal stresses almost up to the point of the ultimate tensile strength. It demonstrates that only a very small fraction of the material remaining in a purely elastic state provides a large stabilising effect resisting necking. A corollary of this is that the uniform elongation of martensitic steel actually increases with increase in the strength level. Effects of heat treatment are also reproduced in the model, including the increase in conventional yield stress (Rp0.2) that occurs after low temperature tempering.

  • 159.
    Hutchinson, Bevis
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB.
    Malmström, Mikael
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB.
    Lönnqvist, Johan
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB.
    Bate, Pete
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB.
    Ehteshami, Hossein
    KTH Royal Institute of Technology, Sweden.
    Korzhavyi, Pavel A
    KTH Royal Institute of Technology, Sweden.
    Elasticity and wave velocity in fcc iron (austenite) at elevated temperatures - Experimental verification of ab-initio calculations.2018Ingår i: Ultrasonics, ISSN 0041-624X, E-ISSN 1874-9968, Vol. 87, s. 44-47, artikel-id S0041-624X(17)31010-7Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    High temperature crystal elasticity constants for face centred cubic austenite are important for interpreting the ultrasonic properties of iron and steels but cannot be determined by normal single crystal methods. Values of these constants have recently been calculated using an ab-initio approach and the present work was carried out to test their applicability using laser-ultrasonic measurements. Steel samples having a known texture were examined at temperatures between 800 °C and 1100 °C to measure the velocity of longitudinal P-waves which were found to be in good agreement with modelled values.

  • 160.
    Irwin, J.
    et al.
    University of the West of England.
    Tidblad, Johan
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Kucera, Vladimir
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Air quality policy2009Ingår i: The Effects of Air Pollution on Cultural Heritage, Springer US , 2009, s. 269-295Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    There are two main ways to protect cultural heritage objects from air pollution damage. First, by reducing ambient levels of air pollution and second, by instigating local management strategies that either reduce the impact of pollution or repair the damage.

  • 161.
    Iyer, Anand H.S
    et al.
    Chalmers University of Technology, Sweden.
    Stiller, Kristyna
    Chalmers University of Technology, Sweden.
    Leijon, Gunnar
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB.
    Andersson-Östling, Henrik C. M.
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB.
    Hörnqvist Colliander, Magnus
    Chalmers University of Technology, Sweden.
    Influence of dwell time on fatigue crack propagation in Alloy 718 laser welds2017Ingår i: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 704, s. 440-447Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The introduction of welded assemblies in aerospace components aid in weight reduction, but also lead to an increased risk of defects. It is therefore important to analyze the high temperature crack growth resistance of such welds. The results from high temperature cyclic and dwell-fatigue testing of surface flawed Alloy 718 welds are presented here. An increasing temperature and application of a dwell time accelerate the crack growth and increase interaction with secondary phases. During cyclic loading at 550 °C, there is little interaction with the microstructure during transgranular propagation, but the application of dwell times results in a mixture of transgranular propagation and intergranular cracking of boundaries between different dendrites. At 650 °C, mixed intergranular and transgranular mode of crack growth is seen under both cyclic and dwell conditions. However, during dwell-fatigue the interfaces between the secondary arms of the same dendrite are also weakened, leading to an interfacial type of crack growth also in the intergranular parts.

  • 162.
    Jablonka, L.
    et al.
    Uppsala University, Sweden.
    Kubart, T.
    Uppsala University, Sweden.
    Gustavsson, F.
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB. Uppsala University, Sweden.
    Descoins, M.
    CNRS-Université d'Aix-Marseille, France.
    Mangelinck, D.
    CNRS-Université d'Aix-Marseille, France.
    Zhang, S. -L
    Uppsala University, Sweden.
    Zhang, Z.
    Uppsala University, Sweden.
    Improving the morphological stability of nickel germanide by tantalum and tungsten additions2018Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 112, nr 10, artikel-id 103102Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    To enhance the morphological stability of NiGe, a material of interest as a source drain-contact in Ge-based field effect transistors, Ta or W, is added as either an interlayer or a capping layer. The efficacy of this Ta or W addition is evaluated with pure NiGe as a reference. While interlayers increase the NiGe formation temperature, capping layers do not retard the NiGe formation. Regardless of the initial position of Ta or W, the morphological stability of NiGe against agglomeration can be improved by up to 100 degrees C. The improved thermal stability can be ascribed to an inhibited surface diffusion, owing to Ta or W being located on top of NiGe after annealing, as confirmed by means of transmission electron microscopy, Rutherford backscattering spectrometry, and atom probe tomography. The latter also shows a 0.3 at. % solubility of Ta in NiGe at 450 degrees C, while no such incorporation of W is detectable. 

  • 163.
    Jacobson, Karin
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Janstål, Martina
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Plastic materials for sulphuric acid services2014Ingår i: Sulphur 2014 30th International Conference and Exhibition, CRU Group , 2014, s. 431-436Konferensbidrag (Refereegranskat)
    Abstract [en]

    The Polymer R&D Group at Swerea KIMAB AB (former Swedish Corrosion Institute) has more than 30 years of experience of the use of polymeric materials in process equipment. The core of our work lies within our membership program "Corrosion Properties of Polymers" where we perform research on questions of special concern for successful and reliable use of plastics in the chemical industry. One of our focus areas is sulphuric acid services where we over the years have worked in close co-operation with material and equipment suppliers and end users and have made a number of failure investigations together with systematic studies in the laboratory. Despite all this work there are still a number of questions concerning the best choice of material and service life of polymers in sulphuric acid services. To tackle this we have together with end-users and suppliers of material and equipment put together a road map for the most important research activities. Our main focus areas have been identified as PVC materials, with a main focus on welding and welding rods, and fluoroplastics for high concentrations >93 wt% and FRP (fiber reinforced plastics) and rubber linings for the concentration range between 72 to 85 wt%.

  • 164.
    Johansson, Adam Johannes
    et al.
    Swedish Nuclear Fuel and waste Management Co (SKB), Sweden.
    Lilja, Christina
    Swedish Nuclear Fuel and waste Management Co (SKB), Sweden.
    Sjögren, Lena
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB.
    Gordon, Andrew
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB.
    Hallbeck, Lotta
    Swedish Nuclear Fuel and waste Management Co (SKB), Sweden.
    Johansson, Linda
    Microbial Analytics AB, Sweden.
    Insights from post-test examination of three packages from the MiniCan test series of copper-cast iron canisters for geological disposal of spent nuclear fuel: impact of the presence and density of bentonite clay2017Ingår i: Corrosion Engineering, Science and Technology, ISSN 1478-422X, E-ISSN 1743-2782, Vol. 52, s. 54-60Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    MiniCan is a field test designed to highlight certain aspects of corrosion in a KBS-3 type repository for spent nuclear fuel. Five experimental packages containing miniature copper-cast iron canisters were installed in the Äspö Hard Rock Laboratory in 2006. Three packages have been retrieved, MiniCan 3 in 2011 and MiniCan 4 and 5 in 2015. The packages were examined regarding surface chemistry, microbiology and corrosion of copper and iron. The main difference in design between the retrieved packages was the presence and density of bentonite clay. Black deposits of sulphides were visually noted during dismantling of both MiniCan 3 (low density clay) and MiniCan 5 (no clay), but not in MiniCan 4 (high density clay). Extensive corrosion of cast iron specimens was observed in all three packages, with local attacks corresponding to the loss of hundreds of µm/y. Sulphate reducing bacteria (SRB) were found to be present in ground water, in bentonite clay and on surfaces of various specimens of iron and copper, and it is suggested that the SRB activity had a pronounced influence on the corrosion observed. Copper surfaces display a roughness at the µm level and the integrated corrosion rate of copper mass-loss specimens was generally low. This paper is part of a supplement on the 6th International Workshop on Long-Term Prediction of Corrosion Damage in Nuclear Waste Systems. © 2017 The Author(s).

  • 165.
    Johansson, Lisen
    RISE, Swerea, Swerea KIMAB AB.
    Methods for assessment of lead release from brass to drinking water2012Rapport (Refereegranskat)
    Abstract [en]

    Mässing är en legering som ofta används i dricksvattenapplikationer såsom kranar, blandare och kopplingar. Mässing innehåller små mängder bly (Pb) som under ogynnsamma förhållanden kan laka ur till dricksvattnet. Många faktorer styr denna urlakning, några av dem är vattnets sammansättning, drifttid, kontakttid, materialets sammansättning, produktens geometri, samt hur den behandlats och tillverkats. Exakt hur och i vilken grad dessa parametrar påverkar urlakningen av Pb från mässing till dricksvatten är inte känt. Syftet med detta examensarbete är att sammanställa den kunskap som finns angående Pb från mässing till dricksvatten, samt experimentellt jämföra tre metoder för godkännande av material; ett europeiskt materialtest, ett skandinaviskt typgodkännande samt ett amerikanskt typgodkännande. Studien visar att en produkt bedöms olika beroende på vilken metod den testas med och att resultaten från produkttester inte går att relatera till resultat i materialtest. De två produkttesterna visade sig ge olika resultat; samtliga prov klarade det skandinaviska testet medan inget prov klarade det amerikanska testet. Vidare visade sig det skandinaviskatestförfarandet för typgodkännande ha stora brister såsom låg repeterbarhet, bristande överensstämmelse med dricksvattendirektivets gränsvärde för Pb samt ett testvatten som sannolikt inte motsvarar ett worst-case. Slutsatsen är att olika testmetoder ger olika utfall, och att korttidstester inte kan användas för att förutspå resultat i ett långtidstest. Det nuvarande skandinaviska typgodkännandet tillåter inte en tillförlitlig långtidsbedömning av produkter.

  • 166.
    Johansson, Sophie Caddeo
    et al.
    RISE, Swerea, Swerea KIMAB AB.
    Frisk, Karin
    RISE, Swerea, Swerea KIMAB AB.
    Surface modification of PM gearlever2010Ingår i: Proceedings of the World Powder Metallurgy Congress and Exhibition, World PM 2010, European Powder Metallurgy Association (EPMA) , 2010, Vol. 3Konferensbidrag (Refereegranskat)
    Abstract [en]

    A novel manufacturing concept for a gearlever has been evaluated by manufacturing of test components of two materials. Iron-based powders were used, and pressing and sintering was followed by a few different variants of hardening and surface densification. The components have been evaluated by means of component function testing, component fatigue testing, microstructure characterization, hardness measurements and residual stress determination. The gearlever is found to perform well in the function testing and shows also good fatigue properties that well match the demands for the intended application. The porosity in the sintered material is inhomogeneous, and some compaction-induced defects were observed in the material, which thus seems not to give any significant negative impact on the sintered product performance. The results show a doubling in hardness after hardening. If the materials were shot-peened (or shot-blasted) after hardening the surface hardness increased down to a depth of approximately 0.2 mm compared to the hardened material. The case-hardening should be applied after shot-peening to obtain significant effect on surface hardness within the outermost 0.1 mm. In principle no surface densification was created if shoot-peening was performed after hardening.

  • 167.
    Jonsson, Sanna
    RISE, Swerea, Swerea KIMAB AB.
    Corrosion of zinc in the automotive environment: Corrosion of zinc in a road environment :relation betweeen corrosion rate, corrrosion products and exposure site2012Rapport (Refereegranskat)
    Abstract [en]

    In a previous project, mobile exposures in road environments have been performed in various areas of the world. A number of materials and coatings have been attached under trailers which travels long distances in different types of road environments. One of the materials, zinc, demonstrated various corrosion rates in different parts of the world. In this investigation two various accelerated corrosion tests have been performed at the laboratory of Swerea KIMAB AB in order to realize parameter influence on zinc. Even though the corrosion rates are known, the relation to formed corrosion products has not been investigated earlier. In the present study, corrosion products on zinc have been analyzed using XRD and FTIR. The results from analyses of formed corrosion products have been evaluated together with measured corrosion rates, both from the mobile exposure and the accelerated tests, in order to try to understand under what conditions certain corrosion products are formed and how it affects the corrosion rate. A cold humid climate was found to be the most corrosive. In these environments, de-icing salts are used which promotes formation of simonkolleite and in a subsequent step; gordaite (if there is a not negligible deposition rate of SO2/SO42-) which is often observed as the end product in marine environments.

  • 168.
    Jönsson, Martin
    et al.
    RISE, Swerea, Swerea KIMAB AB.
    Persson, Dan
    RISE, Swerea, Swerea KIMAB AB.
    The influence of the microstructure on the atmospheric corrosion behaviour of magnesium alloys AZ91D and AM502010Ingår i: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 52, nr 3, s. 1077-1085Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Even though magnesium, as a structure metal, is most commonly used in an atmospheric environment, most investigations of magnesium are performed in solution. In the present work the atmospheric corrosion of two commonly used magnesium alloys, AZ91D and AM50, has been investigated from the initial stages up to the most severe forms of corrosion. A detailed investigation of the morphology of a corrosion attack and its development over time shows that the atmospheric corrosion mechanism is similar for the two alloys. Based on these findings a schematic model of the initial atmospheric corrosion attack on AZ91D is presented and discussed. © 2009 Elsevier Ltd. All rights reserved.

  • 169.
    Jönsson, Martin
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Persson, Daniel
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Corrosion product formation during NaCl induced atmospheric corrosion of magnesium alloy AZ91D2007Ingår i: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 49, nr 3, s. 1540-1558Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Magnesium alloy AZ91D was exposed in humid air at 95% relative humidity (RH) with a deposition of 70 μg/cm-2 NaCl. The corrosion products formed and the surface electrolyte were analysed after different exposure times using ex situ and in situ FTIR spectroscopy, X-ray diffraction and Ion Chromatography. The results show that magnesium carbonates are the main solid corrosion products formed under these conditions. The corrosion products identified were the magnesium carbonates hydromagnesite (Mg5 (CO3)4 (OH)24H2O) and nesquehonite (MgCO3 3H2O). The corrosion attack starts with the formation of magnesite at locations with higher NaCl contents. At 95% RH, a sequence of reactions was observed with the initial formation of magnesite, which transformed into nesquehonite after 2-3 days. Long exposures result in the formation of pits containing brucite (Mg(OH2)) covered with hydromagnesite crusts. The hydromagnesite crusts restrict the transport of CO2 and O2 to the magnesium surface and thereby favour the formation of brucite. Analysis of the surface electrolyte showed that the NaCl applied on the surface at the beginning was essentially preserved during the initial corrosion process. Since the applied salt was not bound in sparingly soluble corrosion products a layer of NaCl electrolyte was present on the surface during the whole exposure. Thus, Na+ and Cl- ions can participate in the corrosion process during the whole time and the availability of these species will not restrict the atmospheric corrosion of AZ91D under these conditions. It is suggested that the corrosion behaviour of AZ91D is rather controlled by factors related to the microstructure of the alloy and formation of solid carbonate containing corrosion products blocking active corrosion sites on the surface.

  • 170.
    Jönsson, Martin
    et al.
    RISE, Swerea, Swerea KIMAB AB.
    Rendahl, Bo
    RISE, Swerea, Swerea KIMAB AB.
    Annergren, Ingegerd
    RISE, Swerea, Swerea KIMAB AB.
    The use of infrared thermography in the corrosion science area2010Ingår i: Materials and corrosion - Werkstoffe und Korrosion, ISSN 0947-5117, E-ISSN 1521-4176, Vol. 61, nr 11, s. 961-965Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The use of infrared (IR) cameras has in recent years gained interest as a non-destructive testing (NDT) technique in a number of different research fields. All objects with a temperature above absolute zero emits IR radiation, and the amount of radiation increases with temperature. Infrared thermography is a non-contact technique with high speed which allows inspection of large areas in a relatively short time. In the present work different aspects of IR thermography are described and discussed. Further, corrosion panels with defects, i.e. blisters and filiform corrosion, have been investigated with pulsed thermography. The area of the blisters and filaments, measured with pulsed thermography, have been evaluated, the result obtained have been compared with results from surface profile measurements of the same area. The differences between the results and the limitations of the pulsed thermography are discussed. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  • 171.
    Jönsson, Martin
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    LeBozec, Nathalie
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Scanning Kelvin probe force microscopy and scanning Kelvin probe in investigation of effect of microstructure on corrosion behaviour of magnesium alloys2007Ingår i: Local Probe Techniques for Corrosion Research, Elsevier Inc. , 2007, s. 111-125Kapitel i bok, del av antologi (Övrigt vetenskapligt)
  • 172.
    Jönsson, Martin
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    LeBozec, Nathalie
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    The influence of microstructure on the corrosion behaviour of AZ91D studied by scanning Kelvin probe force microscopy and scanning Kelvin probe2006Ingår i: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 48, nr 5, s. 1193-1208Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    β-Mg17Al12, η-Al8Mn5 and an α-magnesium phase have been synthesized from pure components by controlled solidification procedures. These phases have been studied using different electrochemical techniques including the scanning Kelvin probe (SKP). From the results, it was possible to determine the nobility and the rate of the cathodic reaction of the different phases. Measurements have also been made on an AZ91D Mg-alloy using scanning Kelvin probe force microscopy (SKPFM) and field emission gun scanning electron microscopy (FEG-SEM). The results show that the Volta potentials measured with the scanning Kelvin probe (SKP) on bulk intermetallics are comparable with those recorded with the SKPFM on the AZ91D alloy. It is shown that SKPFM provides information on the local nobility of the different intermetallic particles and phases on the submicron scale. Both the η-Al8Mn5 phase and the β-Mg17Al12 phase in AZ91D showed a more noble potential than the α-magnesium phase. It is also shown that the aluminium-rich coring along the grain boundaries results in measurable changes in the Volta potential. Finally, the role of the β-Mg17Al12 phase and the η-Al8Mn5 phase in the corrosion behaviour of AZ91D is discussed in term of local nobility, surface coverage of the cathode and the cathodic activity of the different phases.

  • 173.
    Kaijalainen, Antti
    et al.
    University of Oulu, Finland.
    Javaheri, Vahid
    University of Oulu, Finland.
    Lindell, Daniel
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB.
    Porter, David A.
    University of Oulu, Finland.
    Development of crystallographic texture under plane and shear strain in ultrahigh-strength strip steels2018Ingår i: IOP Conference Series: Materials Science and Engineering, 2018, Vol. 375, nr 1, artikel-id 012026Konferensbidrag (Refereegranskat)
    Abstract [en]

    The effect of centerline and subsurface microstructures on the crystallographic texture of three 8 mm thick low-alloyed hot-rolled and direct-quenched ultrahigh-strength strip steels with yield strengths in the range 800 - 1100 MPa has been investigated. Detailed microstructural features were studied using LCSM, FESEM, FESEM-EBSD. In addition textures and crystallographic features were analyzed using Matlab combined with MTEX software. Rolling to lower finish rolling temperatures increased austenite pancaking leading to the formation of ferritic/granular bainitic and the upper bainitic microstructures at the subsurface. In addition, increased austenite pancaking was found to increase the intensities of ∼{554}&lt;225&gt;α, ∼{112}&lt;110&gt;α and ∼{112}&lt;131&gt;α texture components at the centerline and ∼{112}&lt;111&gt;α and ∼{110}&lt;112&gt;α/&lt;111&gt;α texture components in the surface layers, especially in upper bainitic microstructures. Parent austenite reconstruction shows that crystallographic texture at the centerline derived from {112}&lt;111&gt;γ and {110}&lt;112&gt;γ and the subsurface the shear texture components derived from the {112}&lt;110&gt;γ and {111}&lt;112&gt;γ components, as expected. The Matlab reconstruction code was found to work well for martensitic and upper bainitic morphologies even with the highly pancaked prior austenite structure. However, it was less precise for granular bainite and ferrite.

  • 174.
    Karimi, Paria
    et al.
    University West, Sweden.
    Sadeghi, Esmaeil
    University West, Sweden.
    Ålgårdh, Joakim
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB. University West, Sweden.
    Andersson, Joel
    University West, Sweden.
    EBM-manufactured single tracks of Alloy 718: Influence of energy input and focus offset on geometrical and microstructural characteristics2019Ingår i: Materials Characterization, ISSN 1044-5803, E-ISSN 1873-4189, Vol. 148, s. 88-99Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Electron beam melting-powder bed fusion (EBM-PBF) is an additive manufacturing process, which is able to produce parts in layer-by-layer fashion from a 3D model data. Currently application of this technology in parts manufacturing with high geometrical complexity has acquired growing interest in industry. To recommend the EBM process into industry for manufacturing parts, improved mechanical properties of final part must be obtained. Such properties highly depend on individual single melted track and single layer. In EBM, interactions between the electron beam, powder, and solid underlying layer affect the geometrical (e.g., re-melt depth, track width, contact angle, and track height) and microstructural (e.g., grain structure, and primary dendrite arm spacing) characteristics of the melted tracks. The core of the present research was to explore the influence of linear energy input parameters in terms of beam scanning speed, beam current as well as focus offset and their interactions on the geometry and microstructure of EBM-manufactured single tracks of Alloy 718. Increased scanning speed led to lower linear energy input values (<0.9 J/mm) in an specific range of the focus offset (0–10 mA) which resulted in instability, and discontinuity of the single tracks as well as balling effect. Decreasing the scanning speed and increasing the beam current resulted in higher melt pool depth and width. By statistical evaluations, the most influencing parameters on the geometrical features were primarily the scanning speed, and secondly the beam current. Primary dendrite arm spacing (PDAS) slightly decreased by increasing the scanning speed using lower beam current values as the linear energy input decreased. By increasing the linear energy input, the chance of more equiaxed grain formation was high, however, at lower linear energy input, mainly columnar grains were observed. The lower focus offset values resulted in more uniform grains along the 〈001〉 crystallographic direction.

  • 175.
    Karimi, Paria
    et al.
    University West, Sweden.
    Sadeghi, Esmail
    University West, Sweden.
    Åkerfeldt, Pia
    Luleå University of Technology, Sweden.
    Ålgårdh, Joakim
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB. University West, Sweden.
    Andersson, Joel
    University West, Sweden.
    Influence of successive thermal cycling on microstructure evolution of EBM-manufactured alloy 718 in track-by-track and layer-by-layer design2018Ingår i: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 160, s. 427-441Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Successive thermal cycling (STC) during multi-track and multi-layer manufacturing of Alloy 718 using electron beam melting (EBM) process leads to a microstructure with a high degree of complexity. In the present study, a detailed microstructural study of EBM-manufactured Alloy 718 was conducted by producing samples in shapes from one single track and single wall to 3D samples with maximum 10 longitudinal tracks and 50 vertical layers. The relationship between STC, solidification microstructure, interdendritic segregation, phase precipitation (MC, δ-phase), and hardness was investigated. Cooling rates (liquid-to-solid and solid-to-solid state) was estimated by measuring primary dendrite arm spacing (PDAS) and showed an increased cooling rate at the bottom compared to the top of the multi-layer samples. Thus, microstructure gradient was identified along the build direction. Moreover, extensive formation of solidification micro-constituents including MC-type carbides, induced by micro-segregation, was observed in all the samples. The electron backscatter diffraction (EBSD) technique showed a high textured structure in 〈001〉 direction with a few grains misoriented at the surface of all samples. Finer microstructure and possibility of more γ″ phase precipitation at the bottom of the samples resulted in slightly higher (~11%) hardness values compared to top of the samples.

  • 176.
    Karlsson, H.L.
    et al.
    Karolinska Institutet.
    Cronholm, P.
    Karolinska Institutet.
    Hedberg, Y.
    KTH Royal Institute of Technology.
    Tornberg, Malin
    RISE, Swerea, Swerea KIMAB AB.
    De Battice, L.
    Chalmers University of Technology.
    Svedhem, S.
    Chalmers University of Technology.
    Wallinder, I.O.
    KTH Royal Institute of Technology.
    Cell membrane damage and protein interaction induced by copper containing nanoparticles-Importance of the metal release process2013Ingår i: Toxicology, ISSN 0300-483X, E-ISSN 1879-3185, Vol. 313, nr 1, s. 59-69Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Cu-containing nanoparticles are used in various applications in order to e.g. achieve antimicrobial activities and to increase the conductivity of fluids and polymers. Several studies have reported on toxic effects of such particles but the mechanisms are not completely clear. The aim of this study was to investigate the interactions between cell membranes and well-characterized nanoparticles of CuO, Cu metal, a binary Cu-Zn alloy and micron-sized Cu metal particles. This was conducted via in vitro investigations of the effects of the nanoparticles on ( i) cell membrane damage on lung epithelial cells (A549), ( ii) membrane rupture of red blood cells (hemolysis), complemented by ( iii) nanoparticle interaction studies with a model lipid membrane using quartz crystal microbalance with dissipation monitoring (QCM-D). The results revealed that nanoparticles of the Cu metal and the Cu-Zn alloy were both highly membrane damaging and caused a rapid (within 1. h) increase in membrane damage at a particle mass dose of 20. μg/mL, whereas the CuO nanoparticles and the micron-sized Cu metal particles showed no such effect. At similar nanoparticle surface area doses, the nano and micron-sized Cu particles showed more similar effects. The commonly used LDH (lactate dehydrogenase) assay for analysis of membrane damage was found impossible to use due to nanoparticle-assay interactions. None of the particles induced any hemolytic effects on red blood cells when investigated up to high particle concentrations (1. mg/mL). However, both Cu and Cu-Zn nanoparticles caused hemoglobin aggregation/precipitation, a process that would conceal a possible hemolytic effect. Studies on interactions between the nanoparticles and a model membrane using QCM-D indicated a small difference between the investigated particles. Results of this study suggest that the observed membrane damage is caused by the metal release process at the cell membrane surface and highlight differences in reactivity between metallic nanoparticles of Cu and Cu-Zn and nanoparticles of CuO. © 2013 The Authors.

  • 177.
    Karlsson, Oskar
    RISE, Swerea, Swerea KIMAB AB.
    Ageing of brazed aluminium AA6xxx alloys for vehicle radiators2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    Some aluminium alloys with Mg-Si age-hardening are used in vehicle radiators. For cost reasons they are preferably delivered in a naturally aged temper. Estimated minimum time of natural ageing between brazing and when the radiator is taken into service is 14 days. At the service temperature of 95°C, the radiator material will continue to age harden. For accelerated durability testing it is vital to use a radiator with the strength and ageing response of a service radiator. We investigated whether the full 14 days of natural ageing were needed, or if the time could be shortened. Since a vehicle is not in constant use, the radiator temperature will vary over time. We therefore compared cyclic ageing between ambient temperature and 95°C to continuous ageing at 95°C. The Gränges alloys FA7870 (for headers) and FA7850 (for tubes) were subjected to different ageing times at different temperatures. Tensile and hardness were tests performed to assess the ageing effect. It was found that natural ageing reduced hardening during the subsequent ageing at service temperature, an effect that was most pronounced for the first four days. There was no difference between continuous and cyclic ageing. © (2014) Trans Tech Publications, Switzerland.

  • 178.
    Karlsson, Oskar
    et al.
    RISE, Swerea, Swerea KIMAB AB.
    Hagström, Joacim
    RISE, Swerea, Swerea KIMAB AB.
    On the three-dimensional microstructure of martensite in carbon steels2012Ingår i: 1st International Conference on 3D Materials Science 2012, 3DMS 2012, 2012, s. 19-24Konferensbidrag (Refereegranskat)
    Abstract [en]

    The mechanical properties of high-performance steels are often reliant on the hard martensitic structure. It can either be the sole constituent e.g. in tool steels, or it can be part of a multi-phase structure as e.g. in dual-phase steels. It is well-known that the morphology of martensite changes from lath to plate martensite with increasing carbon content. The transition from lath to plate is however less known and in particular the three-dimensional (3D) aspects in the mixed lath and plate region require more work. Here the current view of the 3D microstructure of martensite in carbon steels is briefly reviewed and complemented by serial sectioning experiments using a focused ion beam scanning electron microscope (FIB-SEM). The large martensite units in the Fe-1.2 mass% C steel investigated here are found to have one dominant growth direction, less transverse growth and very limited thickening. There is also evident transformation twinning parallel to the transverse direction. It is concluded that more 3D analysis is required to understand the 3D microstructure of martensite in the mixed lath and plate region and to verify the recently proposed 3D phase field models of martensite in steels.

  • 179.
    Ke, L.
    et al.
    TechnipFMC, France.
    Taravel-Condat, C.
    TechnipFMC, France.
    Kittel, J.
    Institut Français du Pétrole, France.
    Mingant, R.
    Institut Français du Pétrole, France.
    Duret-Thual, Claude
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Querez, Virginie
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Optimizing the design of unbonded flexible pipelines with more realistic predictions of ph and H2s content in the annulus2017Ingår i: Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE, American Society of Mechanical Engineers (ASME) , 2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    Due to its high metallic confinement, the annulus of unbonded flexible pipelines is a specific and mild corrosive medium for carbon steel armour wires. This environment presents high supersaturation levels of dissolved iron, leading to pH values far above thermodynamic equilibrium. Furthermore, the permeation of acidic gases (such as CO2 and H2S) through the polymer pressure sheath occurs at very low flow rates. Since the annulus is supersaturated with dissolved iron, part of the H2S is consumed as it slowly arrives into the annulus. Therefore, the annular medium contains low levels of gas far below those predicted by standard thermodynamic models, and less H2S is available to trigger sour cracking. The recent development of harsher oil field conditions (higher water depths, increased CO2 content, presence of H2S) induced the need to refine the design of flexible pipes to propose more cost effective solutions. As pH and H2S content are key parameters for the selection of steel grades, taking into account the supersaturation and the H2S consumption in the annulus allows major optimization of flexible pipes by using for instance steel grades with higher strength. Therefore, extensive experimental work was conducted over the past years to better characterize the annulus and predict more realistic pH and H2S levels. In this paper, the following developments are presented:-A kinetic corrosion model named FlexCor was derived from numerous corrosion tests done at various CO2 pressures in confined configuration, with in-situ pH monitoring. These tests were performed over long durations (3 months) in order to capture the effective long term supersaturated pH. The kinetic model is able to simulate the transient and stationary phases of the supersaturated pH evolution up to 45 bara of CO2, providing a good fit with the experimental data. The tests also demonstrated that the annulus environment remains supersaturated even at high CO2 partial pressures.-A methodology taking into account the H2S consumption was developed based on extensive longterm small scale and full scale testing (&lt; 2 years), where low flow rates of H2S were imposed. The experimental results show that H2S consumption is far from negligible, even when the annulus is not fully flooded. This H2S consumption methodology was certified by an Independent Verification Agency and is now being applied on commercial projects. 

  • 180.
    Kharitonov, Dmitry S.
    et al.
    KTH Royal Institute of Technology, Sweden; Belarusian State Technological University, Belarus.
    Örnek, Cem
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB. KTH Royal Institute of Technology, Sweden.
    Claesson, Per M
    RISE - Research Institutes of Sweden, Biovetenskap och material, Yta, process och formulering. KTH Royal Institute of Technology, Sweden.
    Sommertune, Jens
    RISE - Research Institutes of Sweden, Biovetenskap och material, Yta, process och formulering.
    Zharskii, Ivan M.
    Belarusian State Technological University, Belarus.
    Kurilo, Irina I.
    Belarusian State Technological University, Belarus.
    Pan, Jinshan
    KTH Royal Institute of Technology, Sweden.
    Corrosion Inhibition of Aluminum Alloy AA6063-T5 by Vanadates: Microstructure Characterization and Corrosion Analysis2018Ingår i: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 5, nr 3, s. C116-C126Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Corrosion inhibition of aluminum alloy AA6063-T5 by vanadates (NaVO3) in 0.05 M NaCl solution has been investigated by electrochemical and weight loss measurements, and associated with microstructure and Volta potential data. X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy analyses confirmed the presence of micrometer-sized Fe-rich Al4.01MnSi0.74, Al1.69Mg4Zn2.31, and FeAl3intermetallic phases (IMPs) and nanometer-sized CuAl2, ZnAl2, and Mg2Si precipitates in the microstructure. Scanning Kelvin probe force microscopy measurements showed Volta potential differences of up to 600 mV between the microstructure constituents indicating a high susceptibility to micro-galvanic corrosion, with interphase boundary regions exhibiting the highest propensity to corrosion. Most IMPs had cathodic character whereas some nanometer-sized Mg-rich particles exhibited anodic nature, with large Volta potential gradients within interphase regions of large cathodic particles. Electrochemical potentiodynamic polarization measurements indicated that the vanadates provided mixed corrosion inhibition effects, mitigating both oxygen reduction, occurring on cathodic IMPs, and anodic metal dissolution reaction, occurring on anodic sites, such as Mg2Si and interphase boundary regions. Electrochemical measurements indicated that the sodium metavanadate inhibitor blocks active metal dissolution, giving high inhibition efficiency (>95%) during the initial exposure, whereas long-term weight loss measurements showed that the efficacy decreases after prolonged exposure.

  • 181.
    Khodaee, Alireza
    et al.
    KTH Royal Institute of Technology, Sweden.
    Melander, Arne
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB.
    Evaluation of effects of geometrical parameters on density distribution in compaction of PM gears2017Ingår i: AIP Conference Proceedings, 2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    The usage of powder metallurgy (PM) for manufacturing of transmission components in automotive industries has been studied by many researchers. PM components have become of interest in recent years due to advancements in post processing possibilities such as hot isostatic pressing (HIP). Still in many of the forming process routes for making components from PM materials, the compaction of the powder into green component is the first step. Compaction is required to put the powder into the near net shape of the desired component and it causes a density gradient in the body of the green component. Basically the friction between powder particles and between the powder particles and die walls are the well-known roots for such density gradients in the compacted component. Looking at forming of PM gears, the gradient in density is one of the most important roots of problems in the processing of PM gears as well. That is because making a gear with full density and no pores will be very costly if large density gradients exist in the green component. The purpose of this study is to find the possible relations between the gear geometry and the density gradients in the green component after compaction in addition to the friction effects. For this purpose several gears should be tested. To reduce the research costs, the finite element (FE) method is used. First a FE model of the compaction process is developed and verified. To investigate the relations between the density gradients and the gear parameters such as addendum diameter (da) and the face width (b) several gear geometries have been studied. The compaction of selected gears is simulated using the FE model. The simulations results which are the distribution of density in the green component are evaluated and discussed and conclusion are made based on them. © 2017 Author(s).

  • 182.
    Khodaee, Alireza
    et al.
    KTH Royal Institute of Technology, Sweden.
    Melander, Arne
    KTH Royal Institute of Technology, Sweden.
    Haglund, Sven
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB.
    The Effects of Blank Geometry on Gear Rolling for Large Gear Modules: Experiments and Finite Element Simulations2018Ingår i: IEEE Access, E-ISSN 2169-3536, Vol. 6, s. 33344-33352Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Gear rolling is a forming process to produce gear wheels by plastic deformation. The advantage of the process is to eliminate the chip formation during production and also to improve the product properties since the non-metallic inclusions will be oriented along the cog surface and not perpendicular to it. The method has been developed in the past years for gear production for automobile application with modules up to 3 mm. The successful application of gear rolling in those cases raises the question regarding the feasibility of using cold rolling to manufacture gears with larger modules which can be used for heavy vehicles. In this paper, a gear wheel with normal module of 4 mm has been studied in order to investigate if such large modules can be manufactured by gear rolling. One of the issues in rolling of gears is the design of the blank geometry in order to obtain the right gear geometry after the rolling process. Blank shape modifications are necessary to control and to reduce the undesired shape deviations caused by the large plastic deformations in rolling. The blank modifications also help the process designer to control the forming force and torque. In this paper, the process has been modeled by finite element simulation and the influence of different blanks has been simulated. The validity of the FE model has been checked through several experiments. Both the numerical and experimental results revealed favorable blank modifications to apply for further developments of the gear rolling process.

  • 183.
    Khurshid, M.
    et al.
    KTH Royal Institute of Technology, Sweden.
    Leitner, M.
    Montanuniversität Leoben, Austria.
    Barsoum, Z.
    KTH Royal Institute of Technology, Sweden.
    Schneider, C.
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB.
    Residual stress state induced by high frequency mechanical impact treatment in different steel grades – Numerical and experimental study2017Ingår i: International Journal of Mechanical Sciences, ISSN 0020-7403, E-ISSN 1879-2162, Vol. 123, s. 34-42Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    High frequency mechanical impact treatment is observed to increase the fatigue strength of welded joints. This technique induces compressive residual stresses, increases the local hardness, and reduces the stress concentration by modifying the weld toe radius. The goal of this study was to investigate residual stresses induced by ultrasonic impact treatment in S355, S700MC, and S960 grades steel experimentally and numerically. Plate specimens were manufactured and treated with different treatment intensities i.e. vibration amplitudes of the Sonotrode. The indentation depths were measured by the aid of a laser scanner and residual stresses using X-ray diffraction technique. The effect of steel grade and treatment intensity on the induced compressive residual stress state was firstly studied experimentally. In addition, displacement controlled simulations were carried out to estimate the local residual stress condition considering the effect of different material models. Both the numerically estimated and experimentally measured residual stresses were qualitatively in good agreement. Residual stress state in S355 and S700MC can be estimated well using combined strain rate dependent material model. No significant effect of the treatment intensity is observed on the indentation depth and residual stress state for S355 grade steel. The indentation depth decreases with the increase in the yield strength of the steel.

  • 184.
    Kouril, Milan
    et al.
    Institute of Chemical Technology, Czech Republic.
    Prosek, Tomas
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Scheffel, Bert
    Fraunhofer, Germany.
    Degres, Yves
    NKE, France.
    Corrosion monitoring in archives by the electrical resistance technique2014Ingår i: Journal of Cultural Heritage, ISSN 1296-2074, E-ISSN 1778-3674, Vol. 15, nr 2, s. 99-103Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    It is essential that corrosion monitoring of indoor atmospheres should be highly sensitive, especially, when corrosion rates corresponding to the lowest standard corrosivity categories are supposed to be identified within one or a few days. The electrical resistance technique in combination with high-sensitivity electrical resistance sensors enabled detection of a corrosion loss on an atomic scale. Case studies have demonstrated the sensors' ability to timely inform the users about changes in the atmosphere quality. In confrontation with quartz crystal microbalance technique, resistometric sensors provided better explainable data.

  • 185.
    Kouøil, M.
    et al.
    University of Chemistry and Technology, Czech Republic.
    Prosek, Tomas
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Dubus, Michel
    Centre de Recherche et de Restauration des Musées de France, France.
    Taube, Michelle
    The National Museum, Denmark.
    Hubert, Vera
    Swiss National Museum, Switzerland.
    Scheffel, Bert
    Fraunhofer, Germany.
    Degres, Yves
    Hennebont, France.
    Jouannic, M.
    Hennebont, France.
    Korozní monitoring v rukách restaurátorù a konzervátorù/Corrosion monitoring in the hands of restorers and conservators2012Ingår i: Koroze a Ochrana Materialu, ISSN 0452-599X, Vol. 56, nr 3, s. 67-75Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A technique for continuous monitoring of atmospheric corrosivity was developed. An electronic unit measures and records changes in the electrical resistance of a thin metal track applied on an insulating substrate. If the metal corrodes, the effective cross-sectional area of the track decreases and the electrical resistance increases. Sensors made of silver, copper, iron / steel, zinc, lead, tin, bronze and brass at thicknesses from 50 nm to 250 Êm were tailored for environments with different corrosivity. The developed technology proved to provide subAngstrom (&lt;10-10 m) sensitivity allowing for real-time corrosion monitoring even in low-corrosive indoor cultural heritage facilities. Laboratory tests showed good reproducibility of the technique with standard deviation of parallel measurements up to ±20% for metals corroding in a given environment mostly uniformly. Since the technique measures the maximal depth of corrosion attack, the response is somewhat higher compared to methods measuring the average corrosion depth. Several examples from a wide testing programme in partner museums, archives, libraries and other institutions were selected to show successful applications of the technique for qualifi cation and comparison of air quality control in indoor premises, assessment of new buildings and storage facilities, air quality control during transport and temporary exhibitions and fundamental studies of optimal conservation and storage procedures. A fi rst outline of a classifi cation system for lead, which is particularly sensitive to presence of carboxylic acids, is given. The technique has a large potential as an independent method of air quality monitoring in facilities.

  • 186.
    Kristoffersen, Hans
    et al.
    RISE, Swerea, Swerea IVF AB.
    Haglund, S.
    RISE, Swerea, Swerea KIMAB AB.
    Influence of straightening on bending fatigue properties of induction hardened shafts in steel 42CrMo4 (SAE 4140)2012Ingår i: Quenching Control and Distortion - Proceedings of the 6th International Quenching and Control of Distortion Conference, Including the 4th International Distortion Engineering Conference, 2012, s. 858-866Konferensbidrag (Refereegranskat)
    Abstract [en]

    Straightening of components after heat treatment is a common procedure in the industry. Typically, elongated components such as shafts and bars are distorted after heat treatment in such a way that straightening is necessary to obtain the desired shape. The straightening operation leads to local plasticisation of the component. This has an effect on for example the residual stress state and the hardness, parameters with strong influence on the fatigue strength of the component. The objective has been to evaluate the influence of straightening on bending fatigue properties, the residual stress state, microstructure and hardness of induction hardened test bars. Straightening was made using three point bending on cylindrical shafts. The residual stress state and hardness were evaluated, before and after straightening. Fatigue testing was performed in three point bending, after rotating the shaft 60 ° after straightening, i.e. towards 120° direction. FEM-simulation of straightening was performed in order to formulate guidelines for straightening. The simulations were performed on a virtually induction hardened shaft of the same dimensions as used in the experiments. It was concluded that straightening affects the residual stress state along the entire circumference of a component. The fatigue strength at 120° was 7% lower after straightening with 80 kN load and 20% lower after straightening with 97 kN load. Residual stresses were affected differently around the perimeter of the shaft. At the point of straightening force application (0°) the compressive residual stresses after heat treating turned to tensile. At the opposite side at 180° the residual stresses turned more compressive than before straightening. At 120° and 240°, the stresses were negatively affected and the residual stresses turned less compressive. The higher of the two straightening forces had even more negative effect on residual stresses. The simulations showed similar changes in residual stresses as were experimentally found. It was concluded that reversed straightening should be avoided and that at higher forces used with combined straightening operations at an angle compared to the desired straightening direction is preferable if larger corrections needs to be done. Copyright © 2012 ASM International® All rights reserved.

  • 187.
    Kucera, Vladimir
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Tidblad, Johan
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Development of atmospheric corrosion in the changing pollution and climate situation2008Ingår i: 17th International Corrosion Congress 2008: Corrosion Control in the Service of Society, 2008, Vol. 3, s. 1877-1891Konferensbidrag (Refereegranskat)
    Abstract [en]

    During a long time SO 2 has been the most important pollutant accelerating atmospheric corrosion of several materials including objects of cultural heritage. The quantification of the effect of pollution has been subject of several projects performed in the last decades in Europe and Northern America ( ICP Materials and MULTI-ASSESS) and in Asia and Southern Africa (RAPIDC). Data from these programmes show that the S-pollution has decreased dramatically in the industrial countries of the temperate zone, while the SO 2 levels are high in several places in the RAPIDC network. Dose-response functions (DRF) have been developed for the new multipollutant situation in the temperate zone containing apart of SO 2 and pH also HNO 3 and particulate matter. The results from temperate zone can not directly be used in subtropical/tropical regions. Recent data will allow development of DRF:s for these regions. The developed DRF:s contain apart of pollution also climatic parameters used in climate change models and they have been used in the NOAHś ARK project for estimations of effects of global climate changes on atmospheric corrosion in Europe. © 2009 by NACE International.

  • 188.
    Larche, Nicolas
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Blanc, Jerome
    DGA Naval Systems, France.
    Iken, I.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Galvanic corrosion induced by the use of high alloy stainless steel in seawater applications2012Ingår i: NACE - International Corrosion Conference Series, 2012, s. 235-253Konferensbidrag (Refereegranskat)
    Abstract [en]

    The galvanic corrosion of carbon steel (UNS G10150) and of copper-nickel 90/10 (UNS C70600) coupled to superduplex stainless steel (UNS S32750) in seawater was investigated from 6°C to 70°C, with different cathode to anode ratios. The effect of chlorination on galvanic corrosion rates was also studied. Continuous monitoring of the open-circuit potentials and galvanic currents were performed to measure the exact evolution and the contribution of the galvanic corrosion on the total corrosion. Results showed that formation of natural biofilms and precipitation of calcareous deposits on surfaces had a very significant impact on the cathodic efficiency, which is directly correlated to the rate of galvanic corrosion. For all the tested configurations, chlorination led to a significant decrease of the measured galvanic currents due to the low cathodic efficiency of surfaces in chlorinated media (i. e. no biofilm). The long term exposure of specimens allowed to draw realistic pseudo-polarization curves which were used in a boundary element modeling software.

  • 189.
    Larche, Nicolas
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Dezerville, Philippe
    Veolia Eau, France.
    Review of material selection and corrosion in seawater reverse osmosis desalination plants2011Ingår i: Desalination and Water Treatment, ISSN 1944-3994, E-ISSN 1944-3986, Vol. 31, nr 1-3, s. 121-133Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Seawater desalination infrastructures require a careful material selection with high corrosion resistance. The high seawater temperatures in warm regions, where many desalination plants are developed, must be clearly considered regarding the corrosion of materials. To comply with the operational characteristics of seawater reverse osmosis (SWRO) process (high pressure, high chloride content and dissolved oxygen content at saturation values), the conventional material selection was stainless steel with sufficient pitting resistant equivalent number. However, many cases of corrosion failures of stainless steel in SWRO desalination units have been reported. In most cases the cause of the failures was attributed to the use of not enough alloyed grades. However, high alloy stainless steels are also susceptible to crevice and pitting corrosion in seawater. The operational corrosion risk will highly depend on the stainless steel composition, on the metallurgy (i.e. cast or wrought), on the service conditions, and on the geometrical configuration of the confined zones in contact with seawater. The present paper reviews the corrosion performance of metallic materials used for SWRO desalination plants. It focuses on the corrosion behaviour of several stainless steel grades. Recent corrosion failures of stainless steel pumps used in SWRO desalination plant in the Mediterranean Sea are also discussed.

  • 190.
    Larche, Nicolas
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Diler, Erwan
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Vittonato, J.
    Total E and P, France.
    Shumovskiy, S.
    Yamal LNG, Russia.
    Cathodic Protection in Arctic Conditions Study Assesses Corrosivity of the Environment at the Yamal LNG Carrier Terminal in Siberia, Russian Federation2018Ingår i: Materials performance, ISSN 0094-1492, Vol. 57, nr 8, s. 26-30Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Yamal LNG, one of the largest liquefied natural gas (LNG) projects in the world, processes natural gas from the giant onshore South Tambey gas and condensate field located on the Yamal Peninsula in the Arctic region of the Russian Federation. Yamal LNG will produce reserves of 4.6 billion bbl (731 billion L) of oil equivalent. The project includes an integrated gas treatment and liquefaction facility with three liquefaction trains (each with a capacity of 5.5 million tons per year), storage tanks, a port with 15 ARC 7 ice-class LNG carriers with a capacity of 170,000 m(3) each, and airport infrastructure.

  • 191.
    Larché, Nicolas
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Blanc, J.
    DGA, France.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Sagebiel, B.
    KME Germany GmbH and Co. KG, Germany.
    Effect of service conditions on the corrosion of nickel-aluminum bronze and copper-nickels alloys in seawater2019Ingår i: NACE - International Corrosion Conference SeriesVolume 2019-March, 2019, Article number 13337Corrosion Conference and Expo 2019; Nashville; United States; 24 March 2019 through 28 March 2019;, National Assoc. of Corrosion Engineers International , 2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    Nickel-Aluminum Bronze (NAB) and Copper-Nickel alloys (CuNi) are commonly used in seawater environments due to their strength combined with a good corrosion resistance and a high resistance to biofouling. However, localized corrosion failures have been reported and are often attributed to abnormal service conditions. The effect of several service condition parameters on the localized corrosion of NAB (UNS C63000, CuAl10Ni5Fe4) and CuNi alloys 90/10 (UNS C70600) and 70/30 (UNS C71500) have been investigated in natural seawater. The results are compared with that of Aluminum-brass (UNS C68700). It includes flow conditions (flowing, quiescent and stagnant), chlorination, sulphide pollution, and crevice geometries. Exposures in both indoor (laboratory) and outdoor tanks (conditions promoting macro fouling) have been tested in temperate and in tropical seawaters. The corrosion stability of the protective oxide layer of the tested copper-based alloys was mainly affected by sulphide pollution in aerated seawater (general corrosion). Under the tested conditions, localized corrosion under-biodeposit clearly appeared as the critical failure for the tested alloys. The conditions for which biodeposit appeared critical for copper-nickel alloys was investigated. 

  • 192.
    Larché, Nicolas
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Dezerville, Philippe
    Veolia, France.
    Le Flour, Denise
    Ifremer, France.
    Corrosion and corrosion management investigations in seawater reverse osmosis desalination plants2013Ingår i: Desalination and Water Treatment, ISSN 1944-3994, E-ISSN 1944-3986, Vol. 51, nr 7-9, s. 1744-1761Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    To comply with the demanding operational conditions of seawater reverse osmosis (SWRO) process, both in terms of corrosion resistance and mechanical properties, the conventional metallic material selection was often stainless steel for seawater and brines handling units (e.g. pumps, valves and piping). However, many cases of corrosion failures of stainless steel in SWRO desalination units have been reported often attributed to un-adapted stainless steel grade selection and/or to the particular aggressive conditions in "warm" regions where many recent desalination plants are built (high ambient temperature, severe biofouling, etc.). The operational corrosion risk will actually highly depend on the material composition, on the metallurgy (i.e. cast or wrought), on the service conditions and on the geometrical configuration of the concerned units in contact with seawater. Considering all these parameters, a proper material selection should avoid corrosion issue. For existing corrosion, cathodic protection (CP) may be an efficient solution to stop or to control the propagation of the degradation. However, the CP for materials used in SWRO desalination plants and in its specific operational conditions (i.e. high pressure, velocity and confinements) is not well documented; as a result, an adapted CP design is not always possible from existing data. The present paper reviews some corrosion cases of stainless steel and copper-based alloys in SWRO desalination plants. Solutions to manage existing corrosion of metallic materials in SWRO plants are discussed and focus is done on CP of stainless steel elements. Some results of an ongoing investigation about the CP for the specific operational conditions of SWRO desalination plant are presented and discussed.

  • 193.
    Larché, Nicolas
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Diler, Erwan
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Crevice and pitting corrosion of stainless-steel and nickel based alloys in deep sea water2019Ingår i: NACE - International Corrosion Conference SeriesVolume 2019-March, 2019, Article number 13337Corrosion Conference and Expo 2019; Nashville; United States; 24 March 2019 through 28 March 2019;, National Assoc. of Corrosion Engineers International , 2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    The exploration and exploitation of deep seawater present promising prospects for many industries. Hence, the use of reliable materials resistant to corrosion in deep seawater conditions is required. In natural seawater, many parameters can influence the kinetics of corrosion such as: temperature, oxygen content, biofilm and fouling activity, flow rates and hydrostatic pressure. For passive materials such as Cr Ni Mo stainless steels and nickel-based alloys, the specificity of the above parameters in deep sea environment might have an impact on both initiation and propagation phases of localized corrosion (e.g. pitting and crevice corrosion), and no or limited field data obtained in deep sea can be found in the literature. Currently, there are still many questions on the corrosion behavior of metallic materials in deep seawater since the results obtained in laboratory or from near-surface seawater cannot be extrapolated to deep seawater environments, especially in terms of bacterial activity which can significantly impact the localized corrosion resistance of passive alloys (cf. biofilm-induced ennoblement). In this study, 13-Cr Ferritic, Austenitic, Lean Duplex, Duplex, Super Duplex, Super Austenitic, Hyper Duplex Stainless Steels and Nickel based alloys were exposed during 11 months at 1020 and 2020 m water depth in the Atlantic Ocean to evaluate their corrosion behavior. Structural carbon steel S355 was also exposed under similar conditions. Polyvinylidene difluoride (PVDF) crevice gaskets according to ISO18070:2015 were used to assess the crevice corrosion at two different gasket pressures, namely 3 and 20 N/mm2. Potential monitoring was performed in-situ (at both 1020 m and 2020 m) in order to characterize the formation of electroactive biofilms at the surface of passive alloys in these environments. At each exposure depth, the environment was characterized using environmental sensors, e.g. temperature, flow velocity, dissolved oxygen, salinity. The obtained results allowed i) ranking the passive material in terms of resistance to pitting and crevice corrosion in deep water at 4°C, ii) comparing biofilm electroactivity and corrosion rates at 1020 and 2020 m depth.

  • 194.
    Larché, Nicolas
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Dézerville, Phlippe
    Veolia Eau, France.
    Le Flour, Denise
    Ifremer, France.
    Vinzio, Pasqual
    KSB SAS, France.
    Köfler, Karl Heinz
    KSB SAS, France.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Corrosion of stainless steel components in seawater reverse osmosis desalination plants—investigations on adapted internal cathodic protection2015Ingår i: Desalination and Water Treatment, ISSN 1944-3994, E-ISSN 1944-3986, Vol. 55, nr 9, s. 2478-2490Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Abstract: Stainless steel is widely used in seawater reverse osmosis units (SWRO) for both good mechanical and corrosion resistance properties. However, many corrosion failures of stainless steel in SWRO desalination units have been reported. These failures may often be attributed to un-adapted stainless steel grade selection and/or to the particular aggressive seawater conditions in “warm” regions (high ambient temperature, severe biofouling, etc.). Cathodic protection (CP) is a well-known efficient system to prevent corrosion of metallic materials in seawater. It is successfully used in the oil and gas industry to protect carbon steel structures exposed in open-sea. However, the specific service conditions of SWRO units may seriously affect the efficiency of such anti-corrosion system (high flow rates, large stainless steel surfaces affected by biofouling, confinement limiting protective cathodic current flow, etc.). Hence, CP in SWRO units should be considered with special care and modeling appears as useful tool to assess an appropriate CP design. However, there is a clear lack of CP data that could be transposed to SWRO service conditions (i.e. stainless steel, effect of biofouling, high flow rate, etc.). From this background a Join Industry Program was initiated including laboratory exposures, field measurements in a full scale SWRO desalination plant, and modeling work using PROCOR software. The present paper reviews the main parameters affecting corrosion of stainless steel alloys in seawater reverse osmosis units. CP on specific stainless steel devices was investigated in order to assess its actual efficiency for SWRO units. Severe environmental conditions were intentionally used to promote corrosion on the tested stainless steel products in order to evaluate the efficiency of CP. The study includes a modeling work aiming at predicting and designing adapted CP protection to modeled stainless steel units. An excellent correlation between modeling work and field measurements was found.

  • 195.
    Larché, Nicolas
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Lang, T.
    Wieland-Werke AG, Germany.
    Internal corrosion of copper-nickel alloy tubes 90/10 and 70/30 in chlorinated seawater for shell and tube heat exchangers2019Ingår i: NACE - International Corrosion Conference SeriesVolume 2019-March, 2019, Article number 13338Corrosion Conference and Expo 2019; Nashville; United States; 24 March 2019 through 28 March 2019;ACE - Int. Corros. Conf. Ser., National Assoc. of Corrosion Engineers International , 2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    The corrosion resistance of copper-nickel 90/10 and 70/30 tubes for heat exchangers was evaluated in 0.5 ppm-chlorinated seawater, under controlled service conditions in a bespoke test loop. The results were compared to Al-Brass tubes tested under the same conditions. Copper-Nickel 90/10 tubes were tested with two different geometries: internal smooth surface and internal finned surface (helix geometry). Internal pitting corrosion resistance was evaluated under simulated heat transfer conditions at two controlled skin temperatures from the internal and the external parts of the tubes for 6 months, at 50°C (Tskin-in)/35°C (Tseawater) and 70°C (Tskin-in)/35°C (Tseawater). For all the tested copper alloys, the uniform corrosion was very low and negligible. For both temperatures, CuNi 90/10 was globally more resistant to localized corrosion than CuNi70/30. The most corrosion resistant configuration was the CuNi 90/10 with the internal finned geometry. The best corrosion resistance compared to the smooth geometry might be attributed to different hydrodynamic conditions at the seawater/metal interface.

  • 196.
    Larché, Nicolas
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Vittonato, J.
    TOTAL, France.
    Diler, E.
    Yamal LNG Marine, Russia.
    Shumovskiy, S.
    Yamal LNG Marine, Russia.
    Field cathodic protection study in the specific artic conditions of the Yamal gas carrier terminal2018Ingår i: NACE - International Corrosion Conference SeriesVolume 2018-April, 2018Corrosion Conference and Expo 2018; Phoenix; United States; 15 April 2018 through 19 April 2018;, National Assoc. of Corrosion Engineers International , 2018Konferensbidrag (Refereegranskat)
    Abstract [en]

    For most projects, cathodic protection (CP) design can be performed using CP standards or existing data from literature and field feed-back. It was not the case for the particular environment of the YAMAL gas carrier terminal project, planned in Sabetta (Siberia - Federation of Russia). This particular area is located between the Kara sea and a river mouth in Yamal peninsula (Artic region). It involves very different conditions in terms of salinity, temperature, liquid/ice phases, all depending on icing/deicing seasons and on the water depth. These very specific conditions can hardly be simulated at laboratory scale and required a specific corrosion and CP study with measurements on site. The global aim of this quantitative study was to collect field data to help at defining an adapted corrosion protection system for carbon steel immerged structure (e. g. berths), and to forecast the related corrosion risks. Regarding the extreme conditions of the site, the main challenge was to design adapted arrays containing corrosion and CP sensors (to be deployed on site), to get representative quantitative data. All systems have been qualified at laboratory scale before use on field site. The deployment was successful and allowed getting actual polarization curves, and local initial corrosion data. In parallel, the stability of zinc galvanic anodes has been evaluated in this resistive environment. For both corrosion and CP data, different results have been highlighted for surface and bottom waters, and for ice & liquid phases. Modelling can now be used to assess the efficiency and select the CP system (i. e. galvanic anode or impressed current)

  • 197.
    Le Bozec, Nathalie
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Joiret, Suzanne
    CNRS, France.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Persson, Daniel
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    The role of chromate conversion coating in the filiform corrosion of coated aluminum alloys2003Ingår i: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 150, nr 12, s. B561-B566Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The mechanisms of inhibition of chromate conversion coating on the filiform corrosion of coated aluminum alloy AA6016 was investigated using X-ray absorption near-edge structure (XANES) spectroscopy and Raman microspectroscopy. The results showed that Cr(VI) was preferably leached out at the opening of the filament, whereas Cr(VI) was reduced to Cr(III) at all other locations. The leached out Cr(VI) accumulated mainly in the pitting area, located in the scratch just outside the filament. The chromate released from the CCC was partly reduced to Cr(III) in the pit. The formation of an Al/Cr mixed oxide was observed in the pitting area. The repassivation of pits in the scratch by the chromate leaching from the CCC close to the scratch explains the low propagation of filiform corrosion observed for the chromated surfaces.

  • 198.
    Le Calve, Philippe
    et al.
    DCN Lorient, France.
    Lacam, Jean Marc
    DGA Centre Technique D'Arcueil, France.
    Lebozec, Nathalie
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Investigating method for the evaluation of the protective performance of paint systems in severe environments of corrosivity category C5-M2004Ingår i: EUROCORR 2004 - European Corrosion Conference: Long Term Prediction and Modelling of Corrosion, 2004Konferensbidrag (Refereegranskat)
    Abstract [en]

    Due to new constraints in environmental legislation, it is necessary to develop suitable methods for the evaluation and the qualification of new protective paint systems. In particular, the need is high for investigating the protection performance of paint systems used in aggressive environments, such as environments of corrosivity category C5-M. The investigating method should be sensitive and relatively quick, give reproducible results and correctly discriminate paint systems. This paper presents results obtained on paint systems in the accelerated corrosion test according to ISO 20340 [1]. The evaluation technique as well as the criteria used for the acceptance of the aging test is discussed. From the results, it is clear that there is a need to develop or adapt sensitive tools to determine underfilm corrosion at early stages. In this view, the scanning Kelvin probe appears to be a promising tool to study the kinetics of delamination at the paint/metal interface.

  • 199.
    Leballeur, Charles
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Larche, Nicolas
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Potential ennoblement of stainless steel: Influence of oxygen content in sea water and pressure2015Ingår i: European Corrosion Congress, EUROCORR 2015, Austrian Society for Metallurgy and Materials (ASMET) , 2015Konferensbidrag (Refereegranskat)
  • 200.
    Lebozec, Nathalie
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Bougon, Laurence
    CEREMA, France.
    Carter, John
    EXOVA, UK.
    Scholz, Tanja
    Fraunhofer IFAM, Germany.
    Knudsen, Ole Øystein
    SINTEF, Norway.
    Flogård, Adeline
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Round-robin evaluation of ISO 20340 annex a test method2016Ingår i: NACE - International Corrosion Conference Series, 2016, s. 53-64Konferensbidrag (Refereegranskat)
    Abstract [en]

    Among available standardized test methods for evaluating the performance of marine and offshore coatings, ISO 20340 Annex A is widely used.1 It is well known that tests performed on presumably identical materials in presumably similar circumstances do not in general yield to identical results. Such deviation is attributed to unavoidable random errors inherent in every test procedure and the fact that the parameters that may influence the outcome of a test cannot all be completely controlled. One consequence of such deviation is that different coating selection may be obtained upon where and how the test is performed, as ISO 20340 Annex A includes acceptance criteria for the selection of coating systems. Thus, to establish the precision of ISO 20340 Annex A, six laboratories participated in a round-robin evaluation of ISO 20340 Annex A test method for the first time. The aim was to estimate the repeatability and the reproducibility of this test upon laboratory, and eventually to determine how to improve the test method and the standard for the further revision of the standard. Five different painted systems applied on abrasive blasted steel were selected so that it included good and poor systems. The results of this study in terms of scribe creep and pull-off strength data were analyzed regarding the repeatability within a laboratory and lab-To-lab reproducibility.

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